Backend Architecture

One deployable, in-process calls, real transactions across the whole domain — and costs that arrive at team boundaries, not at request volume.

One deployable with boundaries the build enforces: most of what services give you, without the network.

Independent deployment and independent failure, bought with every cost that arrives when a function call becomes a network call.

HTTP couples availability and returns an answer; messaging decouples availability and returns a promise. Neither is inherently more scalable.

A slow database becomes timeouts, becomes exhausted workers, becomes an outage in endpoints that never touched the database.

The feedback loops that turn a recoverable degradation into a system that cannot come back up.

Monolith, modular monolith, microservices, serverless and event-driven — when each is useful, what each costs, and how each fails.